C# 根据数据库 自动生成最大编号,应用于各编号的生成

  /// <summary>
        /// 自动生成6位编号,应用于各基本信息中的编号生成
        /// </summary>
        /// <param name="TableName">表名</param>
        /// <param name="FieldName">字段名</param>
        /// <returns></returns>
        public string AutoCreateID(string TableName,string FieldName)
        {
            string Str = "select max(" + FieldName + ") id from " + TableName;//000005
            string maxID = MisLesson.DAL.DbHelperSQL.GetSingle(Str).ToString();//
            if (maxID == "")//000005
            {
                maxID = "000001";
            }
            else
            {
                maxID = (Convert.ToInt32(maxID) + 1).ToString("000000");//
            }
            return maxID;
        }

        /// <summary>
        /// 自动生成14位编号,应用于各业务单据中的编号生成
        /// </summary>
        /// <param name="flag">单据类型标识</param>
        /// <param name="TableName">数据表名</param>
        /// <param name="FieldName">字段名</param>
        /// <returns>返回值:最大编号</returns>
        public string AutoCreateID(string flag, string TableName, string FieldName)
        {
            string sDate = GetServerSysDate("yyyyMMdd");//
            string Str = "select max(" + FieldName + ") id from " + TableName;//
            object obj = MisLesson.DAL.DbHelperSQL.GetSingle(Str);
            string maxID = "";
            if (obj != null)
                maxID =MisLesson.DAL.DbHelperSQL.GetSingle(Str).ToString();//
            
            string Result = "";
            if (maxID == "")
            {
                Result = flag + sDate + "0001";//
            }
            else//
            {
                string sFirstEight = maxID.Substring(2, 8);//
                string sLastFour = maxID.Substring(10, 4);//
                if (sDate == sFirstEight)
                {
                    string sNewLastFour = (Convert.ToInt32(sLastFour) + 1).ToString("0000");//
                    Result = flag + sDate + sNewLastFour;//
                }
                else
                {
                    Result = flag + sDate + "0001";//
                }
            }
            return Result;
        }  /// <summary>
        //